Cast Aluminum Thermostat Housing for A4 chassis TDIs, (ALH). The stock plastic is a weak point in the cooling system on the ALH. The housing gets brittle with age and often breaks (especially the thermostat retaining tabs) when removing to access the thermostat. 
 
Includes O-ring
Lifetime Warranty
 
Volkswagen
Golf TDI MkIV (A4 chassis) w/ ALH Engine (1999-2003)
Jetta TDI MkIV (A4 chassis) w/ ALH Engine (1999-2003)
Jetta Wagon TDI (A4 chassis) w/ ALH Engine (2002-2003)
New Beetle TDI (A4 chassis) w/ ALH Engine (1998-2003)